Worried about my D750

[JosephGozo]

Hello,
My D750 is lubricated with 15w40 motor oil which is changed religiously at 100hr mark (including filter). Tractor is worked hard but never boils over or overheats (has automotive coolant pump). It has clocked up 2362 hrs in my possession over 15 yrs or so. It was bought used and have no idea how many hours were on the clock back then. Engine does not seem to be burning oil.

Issues concerning me
1) Plumes of "white blow by" upon start up and at idle have increased considerably but clears a bit once under load - tilling etc.

2) Engine oil lamp flickers at idle/fast idle after about an hour or less of tilling (at engine rpm full on). last oil change was 87 hrs ago but still went ahead and changed it today. oil was quite thin and watery.

Can worn valve guides or stem seals contribute to the blow by or it is just worn bores/rings? To my knowledge ring wear can also be linked with oil consumption. I will try get its compression tested.

Could switching to Straight 40 oil or 20w50 oil help with the oil pressure issue as a short term measure?

Should I start worrying about replacing standard liners + pistons + bearing shells or getting a good used D950?

Joseph

 

[Dave_eng]

Joseph.
Consider temporarily using a real pressure gauge to determine if the oil pressure really is low or possibly the sending unit is getting tired.
Switching to a thicker oil may solve one issue but create another as startup lubrication may be wanting.
Worn valve guides and seals create oil consumption problems but do not contribute to blow by.
A compression test will be necessary to help you assess the true health of your engine.
The rebuild or replace question has a lot to do with your skills and your access to specialty equipment. A larger used engine may be a good choice as it gets you back in operation much faster.
If the oil pressure is good when measured and the compression is within limits then having the injectors serviced may solve the white smoke at start up.
Dave

 

[DustyRusty]

That is like asking a doctor if you need surgery without a complete analysis of the patient. No way of answering such a broad question without more details.

 

[TheOldHokie]

Hello,
My D750 is lubricated with 15w40 motor oil which is changed religiously at 100hr mark (including filter). Tractor is worked hard but never boils over or overheats (has automotive coolant pump). It has clocked up 2362 hrs in my possession over 15 yrs or so. It was bought used and have no idea how many hours were on the clock back then. Engine does not seem to be burning oil.

Issues concerning me
1) Plumes of "white blow by" upon start up and at idle have increased considerably but clears a bit once under load - tilling etc.

2) Engine oil lamp flickers at idle/fast idle after about an hour or less of tilling (at engine rpm full on). last oil change was 87 hrs ago but still went ahead and changed it today. oil was quite thin and watery.

Can worn valve guides or stem seals contribute to the blow by or it is just worn bores/rings? To my knowledge ring wear can also be linked with oil consumption. I will try get its compression tested.

Could switching to Straight 40 oil or 20w50 oil help with the oil pressure issue as a short term measure?

Should I start worrying about replacing standard liners + pistons + bearing shells or getting a good used D950?

Joseph

Other than the oil light nothing to worry about on an engine with those hours. Thin watery oil and flckering warning light suggests fuel contamination.

Dan

 

[85Hokie]

Issues concerning me
1) Plumes of "white blow by" upon start up and at idle have increased considerably but clears a bit once under load - tilling etc.

AN engine with hundreds of hours will have blow by and smoke at start up - the problem occurs when the smoke DOES NOT go away after 3 or 4 seconds.

2) Engine oil lamp flickers at idle/fast idle after about an hour or less of tilling (at engine rpm full on). last oil change was 87 hrs ago but still went ahead and changed it today. oil was quite thin and watery.

AS DAVE mentioned - need to see what the psi is measuring - I believe the light kicks on below 7 psi.


Could switching to Straight 40 oil or 20w50 oil help with the oil pressure issue as a short term measure?

DO NOT run straight 40 nor the 20w50 - it will be like putting a baidaid on a shark bite - not going to help at all, matter of fact - will hurt more.


I would run it - EVEN if the light flickers, the oil is still moving throughout the system. A "worn" engine is one that is burning or loosing oil and is impossible to start. IF yours starts well, run it !

 

[JosephGozo]

Hello,
Engine exhaust colour is pretty clear and light haze of black under load. This morning after start up i noticed a reduced amount of white blowby. I am going to buy a cheapish compression tester 0to 1000psi should be enough.

I.m handy with spanners jyst finished a top end refurb on my old landrover after a headgasket fail. But i m getting tired and i am afraid that rebuilding the d750 gets too expensive and still be stuck with 16hp. Most complete relining kits on ebay are from china so question quality (at 500€ max)

Start ups are ok from cold after heater (when i apply heaters i count up to 30 or 40 before i crank)

Injectors and pump where checked 2 yrs ago when i stripped the tractor down cor refurb.

Will see... Bloody flu... Idle mind /hands always drive me nuts with regards to equipment! Typical xmas period for me!!!!

 

[Russell King]

Some Kubota engines have a plug in the ends of the camshaft that falls out and creates a low oil pressure problem.
See this thread (many others)

Fish Lifes B6100 Restoration

*This thread is about the complete restoration of my B6100* So, I have to address the low oil pressure issue. Already took the oil pressure sending unit out and used a gauge and confirmed I do indeed have low oil pressure. I suspect the the plug in the cam fell out as other have experienced...

www.orangetractortalks.com

 

[Pau7220]

plug in the ends of the camshaft

My thoughts exactly…..

1) Plumes of "white blow by" upon start up and at idle have increased considerably but clears a bit once under load - tilling etc.

More information is definitely needed.
Exactly where are the plumes coming from?
White smoke from the exhaust is a completely different issue than blow-by from the breather, as is (the possibility of) low oil pressure.

 

[JosephGozo]

Some Kubota engines have a plug in the ends of the camshaft that falls out and creates a low oil pressure problem.
See this thread (many others)

Fish Lifes B6100 Restoration

*This thread is about the complete restoration of my B6100* So, I have to address the low oil pressure issue. Already took the oil pressure sending unit out and used a gauge and confirmed I do indeed have low oil pressure. I suspect the the plug in the cam fell out as other have experienced...

www.orangetractortalks.com

Hi thanks. It looks like a big job to deal with. I will try go through the wsm i have to check exploded views and how to go about it. I have yet to till a patch and check if it flickers/comes on. The thread is quite long btw. ,

 

[JosephGozo]

Hello,

This morning i used the tractor to pull the trailer to carry a load of fresh grass for the sheep.The journey was just 10 minutes each way. When I reached the field it started to idle quite roughly and light was flickering and it wanted to stall. On the return trip after the cutting and collection of the grass it idled ok but the light was full on. Temps on the gauge were still low.

I started stripping up the little one and the timing cover is next to come off. I will change tensioner bearings and fan belt too which looks miserable.

I am using toyota OAT (Red) coolant in the tractor for the past couple of years and I am surprised of how clean the internals of the head and hoses are! no sign of that orange rust deposit.

Here are some photos of the oil oil lamp + temp gauge and of blow by. It reduces during tillage and hard work. (could be the engine being under load forces the rings to seal better against the liner?

REgards.
Joseph

Happy new year to all.

The temp sender is installed at the back of the remote water pump not at the back of the head and at the moment it is barely reading 60'C

 

[b6100bob]

Perhaps engine is worn some. I did have a oil pressure issue several years ago while mowing grass dropped to 5 pounds. No light on though. Went to Kubota dealer asked for a thermostat, he looked in the book. No thermostat convection cooled. He asked a few questions, is radiator in good repair? Too much antifreeze more than 50/50 can cause over heating, I thought no, , took the radiator out almost completely plugged externally with Dandelion fuzz or other debrie. Cleaned with a paper clip and a garden hose and flushed it out inside and outside. Basically overheated boiling the oil dropping oil pressure. Put radiator back in with new 50/50 antifreeze mix no problem since. Replace radiator cap also.

 

[JosephGozo]

Perhaps engine is worn some. I did have a oil pressure issue several years ago while mowing grass dropped to 5 pounds. No light on though. Went to Kubota dealer asked for a thermostat, he looked in the book. No thermostat convection cooled. He asked a few questions, is radiator in good repair? Too much antifreeze more than 50/50 can cause over heating, I thought no, , took the radiator out almost completely plugged externally with Dandelion fuzz or other debrie. Cleaned with a paper clip and a garden hose and flushed it out inside and outside. Basically overheated boiling the oil dropping oil pressure. Put radiator back in with new 50/50 antifreeze mix no problem since. Replace radiator cap also.

Rad clear and clean (recored) less than 3 yrs ago. I have added a coolant pump and temp sender. I am certain it has not over heated. It is late to lift front cover off. Will see tomorrow.


A person told me it may have blown head gasket into the oil gallery some cars tend to do it. Still searching for a compression test.

 

[b6100bob]

Coolant test reveals your winterized for -30? Just ruling out your not frozen up. Yes probably blown head gasket. I have frozen a system before. They are small engines not to difficult to work on. Yes compression test might reveal some information, if your pulling the head check the straightness of the head probably more than .005 thousandths is concerning. shop manual probably has a specifications called out. Also inspection of head for cracks between combustion chambers and within valve areas.

 

[JosephGozo]

hi update.. a really sad one..

The plug on the cam is still on! it is the aluminium type. So what is causing such a drop in oil psi... I am very angry now cos i am suspecting it might have been the switch! I am quite angry cos the first thing i usually install to any of my cars / vehicles is an oil pressure gauge and I never went about installing one on the kubota.

>>>>when i tried undoing the screw that secures the wire, the green plastic housing started spinning along with it and once the screw was removed oil came through its thread - which i do not think is the right way... OH well... I will get a Tee and install and pressure gauge

I do not think the drop is related to running hot because yesterday it came on after only 10 minutes of running close to idle (there is new oil in it too) To add insult to injury yesterday I saw a video onyoutube of a guy who had flickering oil lamp and it was a corroded connection

It is quite warm here in Malta, lowest it gets at the moment is +14

I am thinking
>>>> Could it be that the 3 O rings in the front case have worn out and were messing out the oil flow? they look flat and one of them left a layer (sliced) left behind.
>>>> Should I drill out the aluminium plug and weld on a metal plug ?

Ending the year in style!

thanks.

 

[b6100bob]

hi update.. a really sad one..

The plug on the cam is still on! it is the aluminium type. So what is causing such a drop in oil psi... I am very angry now cos i am suspecting it might have been the switch! I am quite angry cos the first thing i usually install to any of my cars / vehicles is an oil pressure gauge and I never went about installing one on the kubota.

>>>>when i tried undoing the screw that secures the wire, the green plastic housing started spinning along with it and once the screw was removed oil came through its thread - which i do not think is the right way... OH well... I will get a Tee and install and pressure gauge

I do not think the drop is related to running hot because yesterday it came on after only 10 minutes of running close to idle (there is new oil in it too) To add insult to injury yesterday I saw a video onyoutube of a guy who had flickering oil lamp and it was a corroded connection

It is quite warm here in Malta, lowest it gets at the moment is +14

I am thinking
>>>> Could it be that the 3 O rings in the front case have worn out and were messing out the oil flow? they look flat and one of them left a layer (sliced) left behind.
>>>> Should I drill out the aluminium plug and weld on a metal plug ?

Ending the year in style!

thanks.

 

[b6100bob]

I’m not familiar with aluminum plug your talking about. Worn engine main bearings are going give you low oil pressure, probably rod bearings too. 5 pounds of oil pressure for every 1000 RPM you should be fine. I have a oil pressure gauge added by a previous owner. Usually run 40 psi or more when engine at load. It sprung a oil leak 1 time, plastic oil line wore thru. You need to figure out why your not building any warmer temperature in engine.

 

[Russell King]

I would personally try to secure or replace the plug since you have already spent the time getting to it.

If you can get to an illustrated parts list and see if there is a plug at both ends of the camshaft and how hard it is to get to both ends

 

[JosephGozo]

I tried welding up a piece of m6 stud which happened to need a gentle tap with a hammer to go in. And gave it plenty of tacks with the MIG. The alu one came out pretty easy. Yes the gasket is homemade... No time to wait for a gasket to reach me from greece...

I changed the oil lamp switch. I obtained Tee and fittings in 1/8" bspt but sender is 1/8npt. So need to get someone to refresh the thread on the TEEs end where the sender will sit. Hopefully i get to read the pressure. Then will hook up tiller and check the light


Anyhow ... I hope i order engine and gasket kits and head gasket bits and seals and take it off. It has been working hard on the hot end of the guage for a good 9 yrs now. It needs a decoke and valve lapp... If they are not too far gone.

Bloody 2 whole days stuck for nothing.

 

[Russell King]

But you know what is NOT causing the problem now.

Sorry for the red herring in your path to repair.

 

[b6100bob]

What brand and weight motor oil are you running? Diesel rated? Excessively old motor oil not recommended to run. I think they say more than 3 years old. Calls for 10w-30 I believe. I have run 15-40 probably not recommended. To many small passages for it to work thru in the cold.